Fabrication of a Large-area-patterned Monolayer of Polytetrafluoroethylene Nanoparticles by Surface Charge Induced Collo
- PDF / 910,363 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 95 Downloads / 222 Views
Fabrication of a Large-area-patterned Monolayer of Polytetrafluoroethylene Nanoparticles by Surface Charge Induced Colloidal deposition Chuan Du1, Jiadao Wang1, Darong Chen1 1 State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, P.R. China ABSTRACT A facile and novel method of fabricating large-area-patterned monolayer of polytetrafluoroethylene(PTFE) nanoparticles was achieved using surface charge induced colloidal deposition. Chemical processes of amination and hydroxylation were used to make the silicon substrates positively and negatively charged, respectively, while the PTFE colloidal nanoparticles were anisotropic and negatively charged. After colloidal deposition, an ordered monolayer with microholes was formed on the amination surface, while an island-like monolayer was achieved on the hydroxylation surface. Both of the two kinds of monolayers were as large as 1.5 square centimeters. It is worth pointing out that these large-area-patterned monolayers were fabricated without any templates and the whole process only took several hours. The formation mechanism of the different structures can be generally attributed to the cooperation and competition of three-body, two-body and particle-wall interactions. It is believed that the interesting patterned monolayer formation mechanism, high production efficiency, good adaptability and quality will make this novel method attractive. INTRODUCTION Large-area-patterned monolayers have received much attention in recent years due to their wide applications in sensors, catalysis, optical devices, superhydrophobic surfaces, surfaceenhanced Raman scattering and so on [1-3]. At present, methods for fabricating large-areapatterned monolayers are mostly based on templates, including topographical and chemical templates. In general, topographical template method is using the techniques of lithography or monolayer colloidal crystal (MCC) to build a micro/nano patterned substrate which can confine particles into certain positions. For instance, Tianhong Cui et al. reported a lithographic approach to pattern multiple types of layer-by-layer self-assembled nanoparticle (NP) thin films [4]. Lichao Jia et al. generated two-dimensional (2D) ordered porous nanostructures based on 2D colloidal template transfer [5]. Chemical template method is also a common technique employing chemical functionalization patterned template. For this kind of method, particles are attached selectively to a certain area of the template according to hydrophilic/hydrophobic, electrostatic or supramolecular interactions [6]. Many types of patterned nanostructures have been fabricated using chemical templates [7]. However, lithography as a top-down surface-patterning method is usually constrained by high cost, low throughput and lower yield. MCC template as a bottom-up method has more advantages but is hardly to be industrialized, because it is difficult to fabricate large-area-ordered MCC template [8]. Chemical template is often used in combination with the topography templates [9] or Atomic
Data Loading...
